1. Field of the Invention
The disclosure relates to a system and a method for controlling a power line network.
2. Description of Related Art
Electric power is an essential resource in modern society. Power lines are used to transmit the electric power from power plants to each house through substations and outdoor transformers. Besides transmitting power, the power lines in houses and offices can be used to connect control unit devices and network devices. Therefore the power lines, control unit devices, and network devices together can construct a power line network, which is also referred to as a smart grid. Such power line network may use a power line communication (PLC) protocol to provide functions such as remote meter reading, advanced metering infrastructure (AMI), home appliance control, lighting control, and home automation, etc.
FIG. 1 is a schematic diagram of a conventional power line network 100. The power line network 100 has two control networks 120 and 140. Each control network corresponds to a living or working place of a group of people, for example, a family house, a company's office, a store or a factory building, etc. Each control network includes a control unit device and at least one network device, for example, the control network 120 includes a control unit device 122 and network devices 123-125, and the control network 140 includes a control unit device 142 and network devices 143-145. The control unit device is a primary controller of the corresponding control network, and the network devices can be power-consuming devices such as electric appliances or electric meters, etc. Each control network has a corresponding boundary point, the control network 120 corresponds to a boundary point 121, and the control network 140 corresponds to a boundary point 141. The boundary point is a device located between a control network and the external power line network, which is generally an electric switchboard, a no-fuse breaker (NFB) or an electric meter, etc. The range inside the boundary point belongs to the range of the control network. The network devices can not be attached or connected in the area between two boundary points, since normally no electric sockets for the network devices are disposed in the area.
Each control network has a control network identification (CNID). The control unit device and the network devices in a same control network have the same CNID. Since the power line of a densely populated city connects a plurality of houses in series, the control networks of many houses are connected to each other through the power line. The CNID of each control network has to be unique and not be duplicated in the boundary of the signal-reachable power line network.
The power line network has an issue of network demarcation. Since the control networks of the neighbours are all connected and signal-reachable, and if there is no precaution, appliances or lights are probably controlled by the neighbours, or the power company may mistake a digital meter reading of one household as a digital meter reading of another household.